Simplify pattern file structure: redundancy in instance dir names and padding

[vlkl-sap]

Problem statement

Instances currently have the following layout:

102_collection_taint_propagation/2_instance_102_collection_taint_propagation

which creates long, redundant names.

Moreover, directories are currently sorted like this by default:

69_pass_variable_between_java_files
6_callable
70_raw_types

Proposed changes

Consider using one of the following for instances:

102_collection_taint_propagation/instance_002

102_collection_taint_propagation/002

102_collection_taint_propagation/002_further_instnace_detail

In addition consider using padding for filename. While it is possible to use ls -v, consider pading all numbers, i.e., 6 to 006, etc.

[compaluca]

It is a good point.

I would go for the second option: 102_collection_taint_propagation/002

Besides refactoring the testability patterns file structure overall (changing issue title in this respect), this needs to be implemented in the framework as well (see testable-eu/sast-tp-framework#40).

[compaluca]

added padding part